nix support: adjustments pointed out by ruki

Author: ZZBaron

xmake/modules/detect/tools/find_nix.lua

@@ -45,10 +45,15 @@ function main(opt)
         local nix_paths = {
             "/nix/var/nix/profiles/default/bin", -- multi-user installation
             "/home/" .. (os.getenv("USER") or "user") .. "/.nix-profile/bin", -- single user installation
-            "/run/current-system/sw/bin", -- only on nixos, maybe separate nix logic from nixos logic?
             "/usr/local/bin", -- default path of nix when compiling nix from source
         }
+
+        -- NixOS-specific paths
+        if linuxos.name() == "nixos" then
+            table.insert(nix_paths, "/run/current-system/sw/bin")
+        end
 
+        opt.paths = table.wrap(opt.paths)
         for _, nixpath in ipairs(nix_paths) do
             table.insert(opt.paths, nixpath)
         end

xmake/modules/package/manager/nix/find_package.lua

@@ -67,9 +67,7 @@ function _get_available_nix_paths()
             -- Also check for manifest (generation info)
             local manifest = path.join(location, "manifest.nix")
             if os.isfile(manifest) then
-                local manifest_content = try {function()
-                    return io.readfile(manifest)
-                end}
+                local manifest_content = io.readfile(manifest)
 
                 if manifest_content then
                     -- Extract store paths from manifest
@@ -142,17 +140,8 @@ function _find_in_store_path(store_path, name)
         if os.isdir(pcdir) then
             local pcfiles = os.files(path.join(pcdir, name .. ".pc"))
             if #pcfiles > 0 then
-                -- Use pkg-config to get proper info
-                local old_path = os.getenv("PKG_CONFIG_PATH")
-                os.setenv("PKG_CONFIG_PATH", pcdir .. (old_path and (":" .. old_path) or ""))
-                
-                local pcresult = find_package_from_pkgconfig(name)
-                
-                if old_path then
-                    os.setenv("PKG_CONFIG_PATH", old_path)
-                else
-                    os.setenv("PKG_CONFIG_PATH", nil)
-                end
+                -- Use pkg-config with configdirs
+                local pcresult = find_package_from_pkgconfig(name, {configdirs = pcdir})
 
                 if pcresult then
                     return pcresult

xmake/modules/package/manager/nix/install_package.lua

@@ -21,6 +21,7 @@
 -- imports
 import("core.base.option")
 import("lib.detect.find_tool")
+import("private.core.base.is_cross")
 
 -- install package
 --
@@ -39,9 +40,9 @@ function main(name, opt)
         raise("nix not found!")
     end
 
-    -- check architecture (nix supports cross compilation but for simplicity...)
-    if opt.arch ~= os.arch() then
-        raise("cannot install package(%s) for arch(%s)!", name, opt.arch)
+    -- check architecture 
+    if is_cross(opt.plat, opt.arch) then
+        raise("cannot install package(%s) for cross compilation!", name)
     end
 
     local success = false